This application sets forth an improvement of my prior filed application entitled PANEL MOUNTED EXTERIOR KEYED LOCK FOR SLIDING DOORS AND WINDOWS filed Oct. 13, 1977, Ser. No. 841,920, now U.S. Pat. No. 4,154,467 granted May 15, 1979.
This invention relates to locks for sliding doors and windows which not only have frame members which slide by one another but also interlock in the closed mode.
In my previous invention, the screw lock did not automatically retract the bolt and when not properly retracted, damage could occur to the threaded end of the bolt if it was accidentally left protruding beyond the face of the keeper and the door was slammed shut. Further, if the threads in the keeper become stripped, it was not readily apparent from merely turning the key and the door could be forced open.
I have observed that homeowners will spend several thousand dollars on furnishings including expensive television sets, hi-fidelity equipment and then express extreme dismay when all is lost due to a patio door lock which took a burglar less than thirty (30) seconds to pry open. A trip to the local hardware store to buy a secure lock is equally frustrating because there is simply no secure lock available for a sliding interlocking patio door.
A search of existing patents, again does not disclose a solution to the problem. Busby, U.S. Pat. No. 2,018,346 was granted a patent on Oct. 22, 1935 for locking a double hung window. Although he used a threaded bolt, the screws in the lock can be easily pried out since a bar can be placed between frame members 10. Note that the frame members 10 do not interlock with one another. On Sept. 27, 1938, Dunseath was granted U.S. Pat. No. 2,131,315 for a lock for sliding panels on a display case. Again, Rails 4 and 5 of the sliding doors do not interlock with one another.
Crossley invented a lock for an automobile head light and was granted U.S. Pat. No. 1,571,574 on Feb. 2, 1926. Crossley used a threaded bolt, but door 2 did not interlock with housing 1.
Finally, Kaufman, on July 15, 1947 was granted U.S. Pat. No. 2,423,982 for a lock for folding gates. Again, vertical end members 14 and 15 of the gate simply abut one another rather than interlock with one another.
In contrast, this invention discloses a lock for use with frame members which interlock.